1. Field of the Invention
The present invention relates to systems for adjusting and evaluating the positional relationship between a light-receiving element and an optical fiber optically coupled thereto.
The growing demand in recent years for long distance communications has entailed a trend towards higher transmission rates being required of communication systems. Of the communication systems, optical communication systems in particular are required to offer increasingly higher transmission rates on the order of multiple gigabits. Efforts are being made to develop optical communication equipment that would meet the high-speed requirement. In this respect, it is mandatory illustratively for optical receivers to have fast-acting light-receiving elements. Light-receiving elements of this kind are generally small in diameter so as to reduce the element capacitance. Furthermore, single-mode fibers used as high-speed optical transmission paths are also small in diameter. Where a light-receiving element and an optical fiber are to be connected under the constraints above, the positional relationship therebetween needs to be adjusted and evaluated with high precision by appropriate systems. The evaluation of the positional relationship is contingent illustratively on the time-induced deterioration of the efficiency of coupling between light-receiving element and optical fiber.